eea.depiction 0.3 introduces the concept of fallback images when the regular
image traversal fails. The logic works like this:

Look for an image returned by the contexts ‘imgview’ adapter

If the imgview crashes, isn’t found or can not locate/generate an image,
we continue by checking if there’s an image specified for any of the
contexts interfaces.

If there’s no fallback image, we look for an image for the context
portal type, e.g. article, news-item, document. This should be placed
in the ‘portal_depiction’ utility (Site Setup > Depiction Library)

Uses the generic content type image, i.e. portal_depiction/generic

Thus:

To map a fallback image to a portal type, place it in this folder and name
it after the portal type.

To map a fallback image to an interface just add a named-utility for
IDepictionVocabulary (see eea.depiction.vocabularies)

The Initial Owner of the Original Code is European Environment Agency (EEA).
All Rights Reserved.

The eea.depiction (the Original Code) is free software;
you can redistribute it and/or modify it under the terms of the GNU
General Public License as published by the Free Software Foundation;
either version 2 of the License, or (at your option) any later
version.